London: Warming ocean waters are driving the largest movement of marine species in thousands of years, according to a new study.
In the Arctic, melting sea ice during recent summers has allowed a passage to open up from the Pacific Ocean into the North Atlantic, allowing plankton, fish and even whales into the Atlantic Ocean from the Pacific.

The discovery has sparked fears that delicate marine food webs could be unbalanced and lead to some species becoming extinct as competition for food between the native species and the invaders stretches resources, the Telegraph reports.

Rising ocean temperatures are also allowing species normally found in warmer sub-tropical regions to into the northeast Atlantic.

The scientists, who have been collaborating on the Climate Change and European Marine Ecosystems Research project, found the plankton species, called Neodenticula seminae, travelled into the Atlantic through a passage through the Arctic sea ice around that has opened up a number of times in the last decade from the Pacific Ocean.

A venomous warm-water species Pelagia noctiluca has forced the closure of beaches and is now becoming increasingly common in the waters around Britain.

The highly venomous Portuguese Man-of-War, which is normally found in subtropical waters, is also regularly been found in the northern Atlantic waters.

Huge blooms of these marine plants use up the oxygen in the water and can produce toxic compounds that make shellfish poisonous.

Professor Chris Reid, from the Sir Alister Hardy Foundation for Ocean Science at the Plymouth Marine Lab, said: "It seems for the first time in probably thousands of years a huge area of sea water opened up between Alaska and the west of Greenland, allowing a huge transfer of water and species between the two oceans."